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Inorganica Chimica Acta 300–302 (2000) 234–242

Synthesis and characterisation of cobalt, nickel, zinc and cadmiumcompounds with a pyridine-derived N3O2 macrocycle: Crystal and

molecular structures of the macrocyclic ligand andCo(II), Ni(II) and Zn(II) complexes

Laura Valencia a, Harry Adams b, Rufina Bastida a, Andres de Blas c,David E. Fenton b,*, Alejandro Macıas a, Adolfo Rodrıguez a, Teresa Rodrıguez-Blas c

a Departamento de Quımica Inorganica, Uni6ersidad de Santiago, 15706 Santiago de Compostela, Spainb Department of Chemistry, The Uni6ersity of Sheffield, Sheffield S3 7HF, UK

c Departamento de Quımica Fundamental e Industrial, Uni6ersidad de la Coruna, Campus de la Zapateira s/n, 15071 La Coruna, Spain

Received 2 September 1999; accepted 11 November 1999

Abstract

The interaction of Co(II), Ni(II), Zn(II) and Cd(II) with L, a macrocycle containing an N3O2-donor set, has been investigated.The X-ray crystal structures of L, [CoL(NO3)2] (1), [NiL(NO3)2] (2) and [ZnL(H2O)(CH3CN)](ClO4)2 (5) have been determined.The metal atoms in the complexes are coordinated in an endomacrocyclic fashion with the Co and Ni atoms in six-coordinateenvironments comprised of the ligand N3-donor set and two nitrate ions, one monodentate and the other bidentate, giving adistorted octahedral geometry at the metal. In the Zn complex the metal is in a five-coordinate environment comprised of theligand N3-donor set, a water molecule and an acetonitrile molecule, giving a trigonal bipyramidal geometry around the metal.© 2000 Elsevier Science S.A. All rights reserved.

Keywords: Macrocycle complexes; Crystal structures; Template synthesis

1. Introduction

Although the coordination chemistry of macrocyclicligands has been studied extensively during the lastdecades, the coordination capability of the macrocyclicligands towards different metal ions is not entirelypredictable, especially when different donor atoms arepresent. In previous papers [1–5] we have reported thesynthesis and characterisation of metal complexes withseveral NxOy donor atom macrocyclic ligands. We havefound [6] that the reduced ligands L1 and L2 form stablecomplexes with lanthanide ions, while the complexationproperties of these ligands towards the transition metalsand heavy metals are restricted.

As an extension of this work, we have investi-gated the reactions between Co(II), Ni(II), Zn(II) andCd(II) nitrates and perchlorates and the 17-memberedoxaazadiamine macrocycle L, containing an N3O2-donor set, prepared by an in situ reductive demetalla-tion of the corresponding Mn(II) Schiff base complexprepared by Mn(II)-templated cyclocondensation of2,6-diformylpyridine and 1,4-bis(2-aminophenoxy)-butane.

* Corresponding author. Tel.: +44-116-222 9333; fax: +44-115-273 8673.

E-mail address: d.fenton@sheffield.ac.uk (D.E. Fenton)

0020-1693/00/$ - see front matter © 2000 Elsevier Science S.A. All rights reserved.

PII: S 0 0 2 0 - 1 6 9 3 ( 9 9 ) 0 0 5 4 2 - 3

L. Valencia et al. / Inorganica Chimica Acta 300–302 (2000) 234–242 235

2. Experimental

2.1. Measurements

Elemental analyses were performed in a Carlo–ErbaEA microanalyser. Infra-red spectra were recorded asKBr discs on a Bruker IFS-66V. Conductivity measure-ments were carried out in 10−3 mol dm−3 acetonitrilesolutions at 20°C using a WTW LF-3 conductivimeter.FAB mass spectra were recorded on a Kratos-MS-50Tconnected to a DS90 data system, using 3-nitrobenzylalcohol (3-NBA) as matrix material. 1H and 13C NMRspectra were recorded on a Bruker AMX 300 MHzinstrument against TMS as internal standard and DEPT135 and HMQC 1H–13C on a Bruker 500 MHz, CD3CNwas used as deuterated solvent in all cases. 1H NMRtitrations were carried out in CD3CN using a BrukerDPX250Hz spectrometer. Solid-state electronic spectrawere recorded on a Hitachi 4-3200 spectrophotometerusing MgCO3 as reference. Magnetic studies were deter-mined at r.t. on a vibration sample magnetometer (VSM)Digital Measurement System 1660 with a magnetic fieldof 5000 G.

2.2. X-ray structural data: collection and reduction

A brown prismatic crystal of the complex[CoL(NO3)2]·CH3CN (1) and a yellow pale pyramidalcrystal of the complex [ZnL(H2O)(CH3CN)](ClO4)2 (5)were mounted on a glass fiber and used for data collection.Cell constants and an orientation matrix for data collec-tion were obtained by least-squares refinement of thediffraction data from 25 reflections in the range of9.988°BuB20.775° using an Enraf–Nonius MACH3automatic diffractometer and in the range of 19.501°BuB45.789° using an Enraf–Nonius CAD4 automaticdiffractometer, respectively [7]. Data were collected at 293K using Mo Ka radiation (l=0.71073 A, ) for[CoL(NO3)2]·CH3CN (1) and a Cu Ka radiation (l=1.54158 A, ) for [ZnL(H2O)(CH3CN)](ClO4)2 (5) and thev-scan technique, and were corrected for Lorentz andpolarization effects [8]. A semi-empirical absorptioncorrection (8-scan) was made [9]. The ligand L crystallisesfrom acetonitrile as colourless oblongs and the complex[NiL(NO3)2] (2) as blue/green blocks. Three-dimensional,

room temperature X-ray data were collected in the range3.5°B2uB50° on a Siemens P4 diffractometer by the8-scan method. Data were collected using Mo Karadiation (l=0.71073 A, ). For L, of the 2534 reflectionsmeasured, all were corrected for Lorentz and polarisationeffects (but not for absorption), and 860 independentreflections exceeded the significance level �F �/s(�F �)\4.For [NiL(NO3)2] (2), of the 6315 reflections measured, allwere corrected for Lorentz and polarisation effects (butnot for absorption), and 2970 independent reflectionsexceeded the significance level �F �/s(�F �)\4.

2.3. X-ray structural data: structure solution andrefinement (Table 1)

2.3.1. The free macrocycle LThe structure was solved by direct methods which

revealed the position of all non-hydrogen atoms, andrefined on F2 by a full-matrix least-squares procedureusing anisotropic displacement parameters. All hydrogenatoms were included in their calculated positions (C�H0.93–0.97 A, ) and refined using a riding model. Complexscattering factors were taken from the programme pack-age SHELXL93 [10] as implemented on the Viglen 486dxcomputer.

2.3.2. [CoL(NO3)2]·CH3CN (1)The structure was solved by Patterson methods [11] and

subsequent difference Fourier maps, and refined on F2

by a full-matrix least-squares procedure using anisotropicdisplacement parameters [12]. The H atoms were includedin geometrically idealised positions (C�H 0.93–0.97 A, )employing appropriate riding models with isotropicdisplacement parameters constrained to 1.2 Ueq of theircarrier atoms. Two weak peaks were found near N1 andN3 in the Fourier difference synthesis at a locationreasonable for a H atoms. In the final model, these peakswere included as H atoms (H1A and H3A). The absoluteconfiguration was established [13]. Atomic scatteringfactors were taken from ‘International Tables for X-rayCrystallography’ [14] and molecular graphics fromZORTEP [15].

2.3.3. [NiL(NO3)2] (2)The structure was solved by direct methods which

revealed the position of all non-hydrogen atoms, andrefined on F2 by a full-matrix least-squares procedureusing anisotropic displacement parameters. All hydrogenatoms were included in their calculated positions (C�H0.93–0.97 A, ) and refined using a riding model. Complexscattering factors were taken from the programme pack-age SHELXL93 as implemented on the Viglen 486dxcomputer.

2.3.4. [ZnL(H2O)(CH3CN)](ClO4)2 (5)The structure was solved by direct methods which

revealed the position of all non-hydrogen atoms, and

L. Valencia et al. / Inorganica Chimica Acta 300–302 (2000) 234–242236

refined on F2 by a full-matrix least-squares procedureusing anisotropic displacement parameters. All hydro-gen atoms were located in their calculated positions(C�H 0.93–0.97 A, ) and refined using a riding model.Atomic scattering factors were taken from ‘Interna-tional Tables for X-ray Crystallography’ and moleculargraphics from ZORTEP.

22.4. Synthetic procedures

2,6-Diformylpyridine [16] and the diamine 1,4-bis(2-aminophenoxy)butane were prepared according to theliterature methods [17,18]. Metal(II) nitrates andperchlorates were commercial products from Alfa andAldrich Chemicals and used without further purifica-tion. Solvents used were of reagent grade and purifiedby usual methods.

2.4.1. Synthesis of the macrocyclic ligand LThe macrocycle was preparated by a modification of

previously reported procedures [19], the template cyclo-condensation of 1,4-bis(2-aminophenoxy)butane (5mmol) and 2,6-diformylpyridine (5 mmol) in 250 ml ofMeOH using manganese(II) nitrate (5 mmol) as themetal template. The resulting solution was refluxed for2 h and then allowed to cool. Excess of NaBH4 (50mmol) was added carefully in solid incrementalamounts with stirring. When the reduction was com-pleted (ca. 1 h) the solution was filtered and thenconcentrated to give the ligand as a white crystallinesolid (ca. 50% yield). Crystals suitable for X-ray studieswere obtained by recrystallisation from acetonitrile. IR(KBr disc): [n(NH)] 3406 cm−1; mass spectral parention (FAB): m/z 376 [LH]+. (Anal. Found (Calc.) forC23H25N3O2: C, 73.5 (73.6); H, 6.5 (6.7); N, 11.3(11.2)%).

2.4.2. Preparation of the complexesThe appropriate metal(II) salt MX2 (M=Co, Ni, Zn

or Cd and X=NO3− or ClO4

−) (0.5 mmol) was dis-solved in acetonitrile (20 ml) and added to a solution ofL (0.50 mmol) in acetonitrile (30 ml); the mixture washeated to reflux during 3 h and cooled. As a precipitatedid not develop immediately the solution was partiallyconcentrated under vacuum to give a solid, although insome cases the precipitation was aided by addition ofsome diethyl ether (ca. 1 cm3). The products werefiltered off and air dried. Yields: 40–75%. Recrystallisa-tion from acetonitrile yielded crystals suitable to bestudied by X-ray diffraction for 1, 2 and 5.

2.4.3. [CoL(NO3)2] (1)Anal. Found (Calc.) for C23H25N5O8Co: C, 49.4

(50.1); H, 4.7 (4.7); N, 13.3 (14.0)%. IR (KBr, cm−1):3286m [n(NH)], 1604m, 1589w, 1442s [n(C�C) andn(C�N)], 754, 1032, 1311, 1384, 1511 [n(NO3

−)]. MS

(FAB, m/z): 496 [CoL(NO3)]+, 433 [CoL]+, 376[LH]+ . LM/V−1 cm2 mol−1: 148 (1:1).

2.4.4. [NiL(NO3)2] (2)Anal. Found (Calc.) for C23H25N5O8Ni: C, 49.2

(50.1); H, 4.7 (4.7); N, 13.7 (14.0)%. IR (KBr, cm−1):3289m [n(NH)], 1606m, 1585w, 1440s [n(C�C) andn(C�N)], 757, 1039, 1315, 1384, 1508 [n(NO3

−)]. MS(FAB, m/z): 495 [NiL(NO3)]+, 433 [NiL]+, 376 [LH]+.LM/V−1 cm2 mol−1: 150 (1:1).

2.4.5. [NiL(ClO4)2]·3H2O (3)Anal. Found (Calc.) for C23H31N3O13Cl2Ni: C, 39.9

(40.2); H, 4.0 (4.5); N, 6.2 (6.1)%. IR (KBr, cm−1):3431m [n(OH)], 3266m [n(NH)], 1609m, 1585w, 1434s[n(C�C) and n(C�N)], 623, 1104 [n(ClO4

−)]. MS (FAB,m/z): 532 [NiL(ClO4)]+, 433 [NiL]+ .. LM/V−1 cm2

mol−1: 385 (2:1).

2.4.6. [ZnL(NO3)2] (4)Anal. Found (Calc.) for C23H25N5O8Zn: C, 48.8

(49.6), H, 4.7 (4.6); N, 13.5 (13.8)%. IR (KBr, cm−1):3254m [n(NH)], 1607m, 1586w, 1439s [n(C�C) andn(C�N)], 746, 1020, 1315, 1383, 1508 [n(NO3

−)]. MS(FAB, m/z): 501 [ZnL(NO3)]+, 438 [ZnL]+, 376 [LH]+ .

LM/V−1 cm2 mol−1: 152 (1:1).

2.4.7. [ZnL(ClO4)2]·H2O ·CH3CN (5)Anal. Found (Calc.) for C25H30N4O11Cl2Zn: C, 42.9

(42.2); H, 4.3 (4.1); N, 8.0 (7.9)%. IR (KBr, cm−1):3200m [n(OH)], 3285m [n(NH)], 1607m, 1585w, 1436s[n(C�C) and n(C�N)], 623, 1037, 1122 [n(ClO4

−)], 2316,2290 [n(CN)]. MS (FAB, m/z): 538 [ZnL(ClO4)]+, 438[ZnL]+. LM/V−1 cm2 mol−1: 315 (2:1).

2.4.8. [CdL(ClO4)2]·2H2O (6)Anal. Found (Calc.) for C23H29N3O12Cl2Cd: C, 38.2

(39.9); H, 4.0 (4.0); N, 5.8 (6.2)%. IR (KBr, cm−1):3502m [n(OH)], 3239m [n(NH)], 1604m, 1598w, 1446s[n(C�C) and n(C�N)], 620, 1033, 1076, 1124 [n(ClO4

−)].MS (FAB, m/z): 588 [CdL(ClO4)]+, 486 [CdL]+. LM/V−1 cm2 mol−1: 361 (2:1).

3. Results and discussion

The macrocycle ligand L was prepared by an in situreduction of the corresponding Mn(II) Schiff base com-plex and characterised by microanalysis, IR, FAB, MSand NMR spectroscopy (1H and 13C). Hydrogens andcarbon atoms could be assigned by DEPT-135 andHMQC techniques (Table 2). The macrocyclic integrityof L was also confirmed by the X-ray crystal structure(Fig. 1). The reactions between L and nitrates orperchlorates of cobalt, nickel, zinc and cadmium gavein general, good yields of analytically pure products

L. Valencia et al. / Inorganica Chimica Acta 300–302 (2000) 234–242 237

with 1:1 (metal/ligand) stoichiometry, [ML(NO3)2] (M=Co, Ni or Zn) and [ML(ClO4)2]·xH2O·yCH3CN; (M=Ni, Zn or Cd). The presence of the water molecules isconfirmed by the appearance of an intensive broad bandcentred about 3400–3300 cm−1 in the IR spectra of thecomplexes. The bands at about 1600 and 1450 cm−1 areassociated with n(C�N) and n(C�C) vibrations from thepyridine and phenyl rings which undergo a shift towardshigh frequencies on complexation, suggesting interactionbetween the metal and the pyridine nitrogen atom [20].The secondary amine stretches in the region 3290–3240cm−1 which are split and/or shifted relative to that of thefree macrocycle (3400 cm−1) suggest the coordination ofthis group [21]. In the IR spectra of all nitrate complexes,the region associated with the NO stretches shows manybands, and the most intense appear at approximately1440, 1310 and 1250 cm−1, that clearly identify thesespecies as containing coordinate nitrate groups [22,23].The complexity of these bands suggest the presence ofmono- and bidentate nitrate groups, and this was confi-rmed by the X-ray diffraction studies of [CoL(NO3)2] (1)and [NiL(NO3)2] (2).

In the perchlorate complexes, the splitting of the bandattributable to the asymmetric Cl�O stretching mode at1100 cm−1 suggests coordination of the perchlorateanions, but it is probable that in most of the complexesthis splitting may be attributed to the presence of ahydrogen bond interaction between an amine hydrogenatom and one of the perchlorate groups, as is found inthe structure of complex 5.

3.1. Conducti6ity studies

The molar conductance values for the nitrate com-plexes, measured in acetonitrile at 25°C are in the rangecharacteristic of 1:1 electrolytes in this solvent [24], andfor the perchlorate complexes the values, measured underthe same conditions, are in the range characteristic of 2:1electrolytes, indicating the weaker coordination capacityof the perchlorate anion.

3.2. MS-FAB spectra

Positive-ion FAB mass spectrometry provides keyevidence for the formation of the complexes [ML]X2

(M=Co, Ni, Zn, Cd; X=NO3−, ClO4

−). The highest-mass peak in each case corresponds to the generalformulation [MLX]+, and, as is common with complexesof this type, a characteristic fragmentation pattern result-ing from stepwise loss of counterions from the neutralparent complexes is observed. In all cases, peaks corre-sponding to metal-containing fragments [ML]+, arepresent. Furthermore, these fragments lose the metal ionsto give the peak corresponding to the protonated ligand[LH]+.

3.3. NMR spectra

The 1H NMR spectra of the Zn(II) and Cd(II) macro-cyclic complexes exhibit similar features; well resolvedsignals are observed for the pyridine and phenylic rings,and the signals are shifted downfield

Table 1Summary of crystallographic data for the macrocyclic ligand L, [CoL(NO3)2] (1), [NiL(NO3)2] (2) and [ZnL(H2O)(CH3CN)](ClO4)2 (5)

21L 5

Chemical formula C26H28N5O2Co C25H28N6O8Ni C25H30N4O11Cl2ZnC23H25N3O2

Formula weight 375.46 597.46 599.24 698.80Temperature (K) 293(2) 293(2)293(2) 293(2)

monoclinicCrystal system monoclinicmonoclinicorthorhombicSpace group P21/nPnma P21/n Cc

11.200(3)21.307(4)a (A, ) 11.133(4) 17.8092(8)6.1270(12) 14.1440(2)9.023(2)b (A, ) 9.048(4)15.504(3) 15.5948(9)27.050(10)c (A, ) 27.191(6)

119.082(3)98.44(3)98.08(2)b (°)2024.0.(7) 2947.5(2)2706.4(13)Volume (A, 3) 2709(2)4 4Z 4 4

1.5751.4691.466Dcalc (g cm−3) 1.2320.080 0.692m (mm−1) 0.775 3.403800 14401240F(000) 12482534 5526Reflections collected 6315 3178

Independent reflections 2009 5411 4821 31774819/0/3635411/0/3712009/4/253Data/restraints/parameters 3177/2/390

1.033 1.0291.0200.914Goodness-of-fit0.0794 0.0926R a 0.0692 0.0557

wR2b 0.2028 0.2123 0.1682 0.1558

a R=�(�Fo�−�Fc�)/� �Fo�.b Rw= [(�w(�Fo�−�Fc�)2/� w �Fo�2]1/2.

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Table 21H and 13C NMR data of macrocyclic ligand L and complexes 4, 5, 6 a

LAssignment [ZnL(NO3)2] [ZnL(H2O)(CH3CN)][ClO4]2 [CdL][ClO4]2·2H2O

8.12 (t, 1H)Ha 8.08 (t, 1H)7.74 (t, 1H) 8.11 (t, 1H)Hb 6.91 (d, 2H) 7.49 (d, 2H) 7.45 (d, 2H) 7.53 (d, 2H)

4.61 (d, 4H) 4.53 (d, 4H)4.50 (d, 4H) 4.53 (d, 4H)Hc5.65 (t, 2H) 5.45 (t, 2H)Hd 5.11 (t, 2H)5.73 (t, 2H)6.90–7.24 (m, 8H) 6.87–7.22 (m, 8H)6.64–6.88 (m, 8H) 7.12–7.48 (m, 8H)Har

He 4.11 (t, 4H) 3.94 (t, 4H) 3.91 (t, 4H) 4.45 (t, 4H)1.30 (q, 4H) 1.28 (q, 4H)2.06 (q, 4H) 1.98 (q, 4H)Hf

C1 137.6120.5C2

C3 156.447.5C4

C5 136.6109.8C6

C7 120.7116.1C8

110.0C9

146.2C10

67.0C11

26.3C12

a d, doublet; t, triplet; q, quintuplet; m, multiplet.

relative to the free ligand spectrum, indicating coordi-nation of the pyridinic N atom to the metal atom. Thepattern of peak shifts is in accordance with coordina-tion of each of the nitrogen atoms, but gives littleevidence for coordination of the ether donor groups inmost cases.

The He proton signal for the Zn complexes is shiftedupfield, in accordance with the X-ray crystal structureof [ZnL(ClO4)2]·H2O, where both ether oxygen atomsof the macrocycle are not coordinated. However, forthe Cd complex this signal is shifted downfield indicat-ing a possible interaction between the cadmium and theoxygen atoms. The signal of the Hf protons is shifted tohighfield in all cases.

Proton NMR titrations of the macrocycle withZn(ClO4)2·6H2O and Cd(NO3)2·6H2O were performedin CD3CN. Incremental addition of the zinc or cad-mium salts to the ligand solution was found to givesmall shifts in the respective resonances [25]. Thus, incontrast to the usual kinetic inertness of many macro-cyclic systems [26], the present complexes are kineticallylabile as evidenced by the averaging of the free andcomplexes ligand signals. The stoichiometries of metalcomplex formation were obtained by plotting the shiftsof the ligand proton resonance positions as a functionof metal-ion concentration. The effects of incrementaladdition of zinc or cadmium salts on the 1H NMRspectra of the ligand L were similar; the sole formationof a 1:1 (metal:ligand) species being observed in eachcase.

3.4. UV–Vis studies

The solid state electronic spectra of the Co(II) com-plexes show two d–d transition bands in the ranges20800–16700 cm−1 and 10300–9400 cm−1, at-tributable to the 4T1g(P)�4T1g and 4T2g�4T1g transi-tions, that are of the type expected for distortedoctahedral cobalt(II) complexes, while Ni(II) complexesshow three bands at approximately 10500, 17300 and27600 cm−1, which can be attributed to the 3T2g(F)�3A2g, 3T1g(F)�3A2g and 3T2g(P)�3A2g transitions,characteristic of nickel compounds in an octahedralenvironment [27].

3.5. Magnetic moments

The value of the room temperature magnetic momentof the complex [CoL(NO3)2], 4.8 BM, lies within therange usually observed for high-spin octahedral Co(II)complexes (4.7–5.2 BM) [28]. The room temperaturemagnetic moments of the Ni(II) complexes([NiL(NO3)2] and [NiL(ClO4)2]·3H2O) (meff=2.90 and2.80 BM, respectively) lie in the range observed foroctahedral Ni(II) complexes.

3.6. X-ray crystal structures

The molecular structure of L is shown in Fig. 1together with the atomic numbering scheme; bond dis-tances and angles are given in Table 3. The structure

L. Valencia et al. / Inorganica Chimica Acta 300–302 (2000) 234–242 239

Fig. 1. Crystal structure of L.

shows that the ligand is not planar, the planes contain-ing the phenyl rings present an angle of 35° to eachother. The two phenyl rings are each planar (r.m.s.deviation 0.02 and 0.04 A, ). The pyridine ring is alsoplanar (r.m.s. deviation 0.028 A, ) and is inclined at 31.2and 29.5° with respect to the two phenyl rings. In-tramolecular hydrogen bonds are present betweenamine hydrogens and the nearest ether oxygen atoms.

3.6.1. Crystal structure of [CoL(NO3)2] (1)Crystals of [CoL(NO3)2] were grown from acetoni-

trile. The structure of the molecule, with atom labelling,is illustrated in Fig. 2, bond lengths and angles withestimated standard deviations are listed in Table 4. TheX-ray structure analysis shows that the metal is coordi-nated to the three N atoms of the donor set. Theremaining three coordination sites are occupied by Oatoms from one monodentate and one bidentate nitrateligand. The ether oxygen atoms of the macrocyclicligand are not coordinated. The geometry can be de-scribed as distorted octahedral, where the three Natoms of the macrocyclic ligand are in meridional posi-tions. The fourth coordination position of this plane isoccupied by one of the O atoms of the bidentate nitrate

ligand O(22). As might be expected, the pyridine nitro-gen atom provides the strongest bond to cobalt[Co�N(2) 2.028(8) A, , Co�N(1) 2.230(7) A, , andCo�N(3) 2.206(8) A, ]. The Co�O bond distances arealso different, 2.065(6)–2.162(7) A, , the shortest onecorresponding to the monodentate nitrate ligand.

The nitrogen-atom configurations are R,S (or S,R).The pyridine ring is planar (r.m.s. 0.0065 A, ), and it

Table 3Selected bond distances (A, ) and angles (°) for L

1.42(2)N(1)�C(1) N(3)�C(6)1.30(2)1.37(2)O(1)�C(17)1.41(2)N(2)�C(22)

O(2)�C(12)1.37(2)N(3)�C(7) 1.37(2)1.40(2)O(1)�C(16)1.39(2)N(1)�C(5)

1.42(2)N(2)�C(23) 1.45(2)O(2)�C(13)

N(2)�C(22)�C(21)117.7(8) 114(2)C(1)�N(1)�C(5)123.9(14)C(7)�N(3)�C(6) 121.2(13) C(22)�N(2)�C(23)

C(12)�O(2)�C(13) 112.0(14)C(17)�O(1)�C(16)121.1(11)N(1)�C(1)�C(2) 125(2)117(2)N(1)�C(1)�C(23)C(6)�C(5)�N(1)120(2) 117.3(14)C(4)�C(5)�N(1)

117.5(14)C(5)�C(6)�N(3) N(3)�C(7)�C(8) 128(2)112(2)C(22)�C(17)�O(1)118.9(13)N(3)�C(7)�C(12)

121(2)C(17)�C(22)�N(2) N(2)�C(23)�C(1) 112.5(12)

L. Valencia et al. / Inorganica Chimica Acta 300–302 (2000) 234–242240

Fig. 2. Crystal structure of [CoL(NO3)2] (1).

deviation 0.028 A, ) and is inclined 84 and 76° with respectto the two phenyl rings. Intramolecular hydrogen bondsare noted between the amine hydrogens and their nearestether oxygen atoms. Both amine nitrogen atoms formhydrogen-bonded interactions with the oxygen atoms ofthe nitrate groups [N(2)�H(2B)···O(3) 2.244 A, ,N(1)�H(2B)···O(4)* 2.226 A, ] (*symmetry operation [−x+2, −y, −z ]).

The nitrogen-atom configurations are R,S (or S,R).The nickel-donor atom distances are within the expectedrange. The shortest Ni�N bond corresponds to thepyridinic nitrogen atom, Ni�N(3) 1.975(5) A, , and theshortest Ni�O bond distance to the monodentate nitratemolecule, Ni�O(6), 2.069(5) A, . Closely related octahe-dral geometries of macrocyclic ligands around zinc(II)metal atoms have previously been described [29].

3.6.3. Crystal structure of [ZnL(H2O)(CH3CN)](ClO4)2

(5)The structure of the cation is illustrated in Fig. 4.

Table 6 gives bond lengths and angles with estimatedstandard deviations. The metal ion is in a five-coordi-nated environment in which all three N donor atoms ofthe macrocycle are coordinated; the ether O atoms arenot coordinated. The coordination sphere is completedby one acetonitrile molecule and one water molecule.The index of the degree of trigonality (t) within thestructural continuity between square pyramidal andtrigonal bipyramidal geometries has been defined and isequal to 0 and 1 for perfect tetragonal and trigonalgeometries, respectively [30]. Strict application of thederivation of the t index, using the difference between thelargest bond angles present at the metal, leads to t=0.37with O(30) as the apex of a distorted square pyramid. Itis interesting to note that a visual inspection had sug-gested that the geometry could be described as almosttrigonal bipyramidal (tbp) with the axial positions occu-pied by the two amine N atoms, N(1) and N(2). In thisinstance t=0.925 but has been calculated from the thirdlargest difference in angles. The deviation from tbpis clear as N(1)�Ni�N(2) is not linear but subtends

Table 4Selected bond distances (A, ) and angles (°) for [CoL(NO3)2] (1)

2.162(7)Co(1)�N(2) Co(1)�O(21)2.028(8)Co(1)�O(11) 2.065(6) Co(1)�N(3) 2.206(8)

2.230(7)Co(1)�N(1)2.125(7)Co(1)�O(22)

99.4(3)N(2)�Co(1)�O(11) 93.9(3) O(22)�Co(1)�N(3)175.7(3) 97.7(3)O(21)�Co(1)�N(3)N(2)�Co(1)�O(22)90.4(3)O(11)�Co(1)�O(22) N(2)�Co(1)�N(1) 79.0(3)

N(2)�Co(1)�O(21) 115.4(3) O(11)�Co(1)�N(1) 85.6(3)O(11)�Co(1)�O(21) 149.2(3) O(22)�Co(1)�N(1) 102.0(3)

60.5(3)O(22)�Co(1)�O(21) O(21)�Co(1)�N(1) 90.6(3)N(3)�Co(1)�N(1)79.5(3)N(2)�Co(1)�N(3) 158.5(3)

96.8(3)O(11)�Co(1)�N(3)

forms angles of 76 and 85° with the phenolic rings, beingtilted at an angle of 77° to each other.

3.6.2. Crystal structure of [NiL(NO3)2] (2)The molecular structure of this complex is shown in

Fig. 3 together with atomic numbering. Selected bonddistances and angles appear in Table 5. The structure ofthe compound is similar to that described above beingbuilt up of discrete molecules with the nickel atomcoordinated by one macrocyclic ligand through the Natoms, and through three O atoms of two nitratemolecules. The environment around the metal is again adistorted octahedron, with the three N atoms in merid-ional positions and one O atom of the bidentate nitrateligand occupying the fourth coordination position of thisplane. The ether oxygen atoms of the macrocyclic ligandare not coordinated. The distortion is due to the smallbite of the bidentate nitrate ligand, O(6)�Ni(1)�O(7),60.9(2)°. In the macrocyclic ligand the two planar phenylrings, (r.m.s. 0.008 and 0.01 A, ) are tilted at an angle of76° to each other. The pyridine ring is planar (r.m.s.

Table 5Selected bond distances (A, ) and angles (°) for [NiL(NO3)2] (2)

Ni(1)�O(5)Ni(1)�N(3) 1.975(5) 2.050(4)2.069(5) Ni(1)�N(2) 2.146(5)Ni(1)�O(6)2.165(4) Ni(1)�N(1)Ni(1)�O(7) 2.173(4)

N(3)�Ni(1)�O(6)92.1(2)N(3)�Ni(1)�O(5) 174.0(2)N(3)�Ni(1)�N(2) 81.1(2)O(5)�Ni(1)�O(6) 93.6(2)

94.1(2) O(6)�Ni(1)�N(2)O(5)�Ni(1)�N(2) 100.2(2)O(5)�Ni(1)�O(7) 154.0(2)113.2(2)N(3)�Ni(1)�O(7)N(2)�Ni(1)�O(7) 95.7(2)O(6)�Ni(1)�O(7) 60.9(2)

86.3(2)O(5)�Ni(1)�N(1)N(3)�Ni(1)�N(1) 80.5(2)98.1(2) N(2)�Ni(1)�N(1)O(6)�Ni(1)�N(1) 161.6(2)91.8(2)O(7)�Ni(1)�N(1)

L. Valencia et al. / Inorganica Chimica Acta 300–302 (2000) 234–242 241

Fig. 3. Crystal structure of [NiL(NO3)2] (2).

an angle of 160.7°, the zinc atom is 0.0557 A, out of theequatorial plane provided by N(1), N(3) and O(30) andtwo of the in-plane angles at the metal deviate signifi-cantly from the 120° predicted for a trigonal bipyramid(105.2 and 138.7°).

The conformation of the macrocycle is such that thetwo planar phenyl rings (r.m.s. 0.008 and 0.01 A, ), are

tilted at an angle of 76°. The configuration of the aminenitrogens are S,R (or R,S). The Zn�N bond distancesvary from 1.996(5) A, [Zn�Npyr] to 2.223(5) A,[Zn�Namine], and are in the range anticipated for five-coordinate zinc(II). The Zn�O bond distance is 2.014(5)A, , the value expected for a water molecule coordinatedto zinc(II). The perchlorate groups are not coordinatedto the metal atom, but form hydrogen-bonded interac-tions, (N1)�H···O(21)=2.14 A, and (N2)�H···O(11)*=2.52 A, (*symmetry operation [x+1/2, −y+3/2,z−1/2]). Similar trigonal bipyramidal geometries in-volving zinc coordinated by macrocyclic ligands havepreviously been described [31].

Fig. 4. Crystal structure of [ZnL(H2O)(CH3CN)](ClO4)2 (5).

Table 6Selected bond distances (A, ) and angles (°) for [ZnL(H2O)-(CH3CN)][ClO4]2 (5)

Zn(1)�N(1) 2.202(5)Zn(1)�N(3) 1.996(5)2.014(5) Zn(1)�N(2)Zn(1)�O(30) 2.223(5)

Zn(1)�N(30) 2.037(6)

96.4(2)N(30)�Zn(1)�N(1)N(3)�Zn(1)�O(30) 116.0(3)80.07(18)N(3)�Zn(1)�N(2)N(3)�Zn(1)�N(30) 138.7(2)

O(30)�Zn(1)�N(2) 95.6(2)O(30)�Zn(1)�N(30) 105.2(3)N(30)�Zn(1)�N(2) 99.0(2)N(3)�Zn(1)�N(1) 80.68(18)

91.4(2) N(1)�Zn(1)�N(2)O(30)�Zn(1)�N(1) 160.70(18)

L. Valencia et al. / Inorganica Chimica Acta 300–302 (2000) 234–242242

Acknowledgements

We thank the Xunta de Galicia (PGIDT99PXI20902B), Spain for financial support and the EP-SRC for funds towards the purchase of adiffractometer.

References

[1] R. Bandın, R. Bastida, A. de Blas, P. Castro, D.E. Fenton, A.Macıas, A. Rodrıguez, T. Rodrıguez-Blas, J. Chem. Soc., DaltonTrans (1994) 1185.

[2] R. Bastida, A. de Blas, P. Castro, D.E. Fenton, A. Macıas, R.Rial, A. Rodrıguez, T. Rodrıguez-Blas, J. Chem. Soc., DaltonTrans. (1996) 1493.

[3] H. Adams, R. Bastida, A. de Blas, M. Carnota, D.E. Fenton, A.Macıas, A. Rodrıguez, T. Rodrıguez-Blas, Polyhedron 16 (1997)567.

[4] C. Lodeiro, R. Bastida, A. de Blas, D.E. Fenton, A. Macıas, A.Rodrıguez, T. Rodrıguez-Blas, Inorg. Chim. Acta 267 (1998) 55.

[5] E. Bertolo, R. Bastida, A. de Blas, D.E. Fenton, A. Macıas, A.Rodrıguez, T. Rodrıguez-Blas, A. Villar, Z. Naturforsch., Teil B53 (1998) 1445.

[6] L. Valencia, R. Bastida, A. de Blas, D.E. Fenton, A. Macıas, A.Rodrıguez, T. Rodrıguez-Blas, A. Castineiras, Inorg. Chim. Acta282 (1998) 42.

[7] B.V. Nonius, CAD4-Express Software, Version 5.1/1.2. Enraf–Nonius, Delft, The Netherlands, 1994.

[8] M. Kretschmar, GENHKL, Programme for the reduction ofCAD4 Diffractometer data, University of Tubingen, Germany,1997.

[9] A.C.T. North, D.C. Phillips, F.S. Mathews, Acta Crystallogr.,Sect. A 42 (1968) 351.

[10] G.M. Sheldrick, SHELXL-93, An integrated system for solvingand refining crystal structures from diffraction data, Universityof Gottingen, Germany, 1993.

[11] G.M. Sheldrick, Acta Crystallogr., Sect. A 46 (1990) 467.

[12] G.M. Sheldrick. SHELXL-97, Program for the refinement ofcrystal structures, University of Go9 ttingen, Germany, 1997.

[13] H.D. Flack, Acta Crystallogr., Sect. A 39 (1983) 876.[14] International Tables for X-ray Crystallography, Vol C, Kluwer,

Dordrecht, The Netherlands, 1995.[15] L. Zoslnai. ZORTEP, A programme for the presentation of ther-

mal ellipsoids. University of Heidelberg, Germany, 1997.[16] D. Jerchel, J. Heider, H. Wagner, Liebigs Ann. Chem. 613 (1958)

153.[17] P.A. Tasker, E.B. Fleischer, J. Am. Chem. Soc. 92 (1970) 7072.[18] R.D. Caannon, B. Chiswell, L.M. Venanzi, J. Chem. Soc. A

(1967) 1277.[19] D.E. Fenton, B.P. Murphy, A.J. Leong, L.F. Lindoy, A.

Bashall, M. McPartlin, J. Chem. Soc., Dalton Trans. (1987)2543.

[20] N.S. Gill, R.H. Nuttall, D.E. Scaife, J. Inorg. Nucl. Chem. 18(1981) 79.

[21] N.A. Bailey, D.E. Fenton, S.J. Kitchen, J. Chem. Soc., DaltonTrans. (1991) 627.

[22] J.-C.G. Bunzli, D. Wessner, Coord. Chem. Rev. 191 (1984) 253.[23] W.T. Carnall, S. Siegel, J.R. Ferraro, B. Tani, E. Gebert, Inorg.

Chem. 12 (1973) 560.[24] W.J. Geary, Coord. Chem. Rev. 7 (1971) 81.[25] L.F. Lindoy, H.C. Lip, J.H. Rea, R.J. Smith, K. Henrick, M.

McPartlin, PA. Tasker, Inorg. Chem. 19 (1980) 3360. J.C. Lock-hart, A.C. Robson, M.E. Thompson, P.D. Tyson, I.H.M. Wal-lace, J. Chem. Soc., Dalton Trans. (1978) 611.

[26] L.F. Lindoy, Chem. Soc. Rev. 4 (1975) 421.[27] A.B.P. Lever, Inorganic Electronic Spectroscopy, 2nd Edition,

Elsevier, Amsterdam, 1984.[28] B.N. Figgis, Introduction to Ligand Fields, Interscience, New

York, 1967.[29] H. Adams, N.A. Bailey, D.E. Fenton, S.J. Kitchen, B.A. Najera,

Anal. Quim. 93 (1997) 88.[30] A.W. Addison, T.N. Rao, J. Reedijk, J. van Rijn, G.C. Ver-

schoor, J. Chem. Soc., Dalton Trans. (1984) 1349.[31] K.R. Adam, S.P.H. Arshad, D.S. Baldwin, P.A. Duckworth,

A.J. Leong, L.F. Lindoy, B.J. McCool, M. McPartlin, B.A.Tailor, P.A. Tasker, Inorg. Chem. 33 (1994) 1194.

.